scholarly journals Guided Wave Energy Transfer in Composite Sandwich Structures and Application to Defect Detection

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Siavash Shoja ◽  
Viktor Berbyuk ◽  
Anders Boström
Keyword(s):  
Finite Element ◽  
Wave Energy ◽  
Guided Waves ◽  
Sandwich Structures ◽  
Guided Wave ◽  
Core Material ◽  
Energy Transmission ◽  
Composite Sandwich ◽  
Composite Sandwich Structures ◽  
Homogenization Methods

In this study, energy transmission of the guided waves propagating in composite sandwich structures is investigated in a wide range of frequencies using numerical simulations. The effects of different potential defects on the guided wave energy transmission are explored in such structures. Furthermore, the accuracy of homogenization methods for finite element modelling of guided wave propagation in sandwich structures is studied with the aim of reducing the computational burden of the simulations in the low range of frequencies. A 2D finite element model is developed and verified by comparing the results with the dispersion curves. In order to examine homogenization methods, the homogenized stiffness matrices of the sandwich material and the laminate skin are calculated using classical laminate theory. Results show that core-skin debonding causes absence of wave energy leakage from the skin to the core material in that region in a specific range of frequencies. The results are also obtained for the delamination within the skin and compared with the healthy material. Finally, for the guided waves in the low range of frequencies, it is possible to use the homogenization methods to create the finite element models and reduce the solution time.

NUMERICAL MODEL OF TUBULAR COMPOSITE SANDWICH STRUCTURES UNDER LOW-VELOCITY IMPACT

2021 ◽  
Author(s):  
CHAO ZHANG ◽  
ISAIAH KAISER ◽  
K. T. TAN
Keyword(s):  
Sandwich Structures ◽  
Matrix Cracking ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Low Velocity ◽  
Damage Mechanisms ◽  
Velocity Impact ◽  
Composite Sandwich ◽  
Composite Sandwich Structures

This study aims to investigate the dynamic impact response of tubular composite structures with honeycomb sandwich core under transverse low-velocity impact (LVI) test. We establish a finite element analysis (FEA) model of composite sandwich structures. Simulation results are compared with experimental results to verify the correctness of the model and analysis method. This model can accurately predict the impact response and damage mechanisms of a composite sandwich structure, as validated by experimental testing, specifically capturing major failure modes. LVI experiments are conducted utilizing cylindrical impact striker to enact both point and line impact. Damage mechanisms, such as matrix cracking, delamination, and fiber breakage/rupture, occur in the facesheet, as well as honeycomb crushing and breakage in the core. The combination of experimental and numerical results illustrates the effects of facesheet thickness and core thickness on failure mechanisms. A three-dimensional model can also be used to clearly visualize the effect of different core material properties on the failure mechanism and dynamic response during an impact event.

Guided Wave Based Damage Assessment in X-COR Composite Sandwich Structures

2017 ◽  
Author(s):  
Guoyi Li ◽  
Rajesh Kumar Neerukatti ◽  
Abhishek Rajadas ◽  
Aditi Chattopadhyay ◽  
Daniel Huff
Keyword(s):  
Damage Assessment ◽  
Sandwich Structures ◽  
Guided Wave ◽  
Composite Sandwich ◽  
Composite Sandwich Structures

Symbolic dynamics time series analysis for assessment of barely visible indentation damage in composite sandwich structures based on guided waves

2017 ◽  
Vol 51 (29) ◽  
pp. 4129-4143 ◽  
Author(s):  
Mohammad Ali Fakih ◽  
Samir Mustapha ◽  
Mehrisadat Makki Alamdari ◽  
Lin Ye
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Static Loading ◽  
Guided Waves ◽  
Sandwich Structures ◽  
Composite Sandwich ◽  
Series Analysis ◽  
Composite Sandwich Structures ◽  
Symbolic Time Series Analysis ◽  
Indentation Damage

This study addresses the detection and localization of barely visible indentation damage in composite sandwich structures using ultrasonic guided waves. A quasi-static loading was gradually applied on a specimen of carbon fiber reinforced epoxy with honeycomb core, with the resulting dent size varying between 0.2 and 2.7 mm. The fundamental symmetric (S0) Lamb wave mode was excited to interrogate the structure. An anomaly measure was established based on symbolic time series analysis; it was defined as the ratio between the norms of probability vectors obtained from the symbol sequence vectors before and after damage has occurred. The symbolic time series analysis method transforms time series data into symbol sequences according to a pre-constructed symbol space using a set number of partitions. The number of partitions selected was determined based on the maximum Shannon’s entropy approach. An imaging algorithm was adopted in order to localize the damage. The effects of the excitation frequency and the number of partitions on the precision of prediction were investigated. The adopted approach showed high sensitivity to a very small change of 0.2 mm on the surface panel after a quasi-static loading of 2-mm indentation. Furthermore, the ability of the method to detect progressive damage was demonstrated. The results obtained demonstrate that symbolic time series analysis has excellent potential for use in detecting small defects such as barely visible indentation damage.

Effects of honeycomb core damage on the performance of composite sandwich structures

2019 ◽  
Vol 54 (16) ◽  
pp. 2159-2171
Author(s):  
William T King ◽  
William E Guin ◽  
J Brian Jordon ◽  
Mark E Barkey ◽  
Paul G Allison
Keyword(s):  
Finite Element ◽  
Shear Modulus ◽  
Composite Structures ◽  
Sandwich Structures ◽  
Honeycomb Core ◽  
Element Analysis ◽  
Composite Sandwich ◽  
Core Damage ◽  
Composite Sandwich Structures ◽  
Aluminum Honeycomb

This work presents an experimental and numerical investigation of the effects of pre-existing core damage on aluminum honeycomb core composite sandwich structures. Quasi static flexural and compression experiments were performed, where the effects of core damage on the shear modulus and Young's modulus were quantified. In addition, finite element analysis was performed on the sandwich structures to elucidate the effects of the core damage on the structural response. Comparisons of experimental and finite element responses are presented for sandwich structures consisting of carbon fiber facesheets and an aluminum honeycomb core. The pre-existing core damage is observed to cause up to an 8% reduction in shear modulus and a 9% reduction in elastic modulus. It is also determined that the presence of pre-existing core damage results in an asymmetrical compressive load distribution in the composite structures.

Debonding Detection in Composite Sandwich Structures Based on Guided Waves

AIAA Journal ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 1697-1706 ◽  
Author(s):  
Samir Mustapha ◽  
Lin Ye ◽  
Dong Wang ◽  
Ye Lu
Keyword(s):  
Guided Waves ◽  
Sandwich Structures ◽  
Composite Sandwich ◽  
Composite Sandwich Structures ◽  
Debonding Detection

scholarly journals Manufacture of Green-Composite Sandwich Structures with Basalt Fiber and Bioepoxy Resin

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
J. P. Torres ◽  
R. Hoto ◽  
J. Andrés ◽  
J. A. García-Manrique
Keyword(s):  
Numerical Simulations ◽  
Sandwich Structures ◽  
Basalt Fiber ◽  
Core Material ◽  
Material System ◽  
Green Composite ◽  
Fem Simulations ◽  
Composite Sandwich ◽  
Composite Sandwich Structures ◽  
Mould Filling

Nowadays, there is a growing interest for the use and development of materials synthesized from renewable sources in the polymer composites manufacturing industry; this applies for both matrix and reinforcement components. In the present research, a novel basalt fibre reinforced (BFR) bioepoxy green composite is proposed as an environmentally friendly alternative to traditional petroleum-derived composites. In addition, this material system was combined with cork as core material for the fabrication of fibre composite sandwich structures. Mechanical properties of both skin and core materials were assessed through flexural and tensile tests. Finite element (FEM) simulations for the mechanical stress analysis of the sandwich material were carried out, and a maximum allowable shear stress for material failure under bending loads was established. Permeability measurements of the basalt fabrics were carried out in order to perform numerical simulations of liquid composite moulding (LCM) processes on the PAM-RTM software. The proposed green-composite sandwich material was used for the fabrication of a longboard as a case study for a sports equipment application. Numerical simulations of the mould filling stage allowed the determination of an optimal mould filling strategy. Finally, the load-bearing capacity of the board was studied by means of FEM simulations, and the presented design proved to be acceptable for service.

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